Hello,
It's working correctly. Please run the following simple code:
$docx = new CreateDocx();
$html = '<p><img src="image.png" width="90" height="90"></p>';
$docx->embedHTML($html, ['useHTMLExtended' => true]);
$docx->customizeWordContent(['type' => 'image'], ['imageAlign' => 'center']);
$docx->createDocx('output');
HTML sets a default left align. Then the customizeWordContent method sets a center align to the image.
Maybe your HTML is floating the image, so MS Word ignores the alignment, or some other parent style of the image is applying another alignment to the image.
Regards.